Chassis height adjustable jack and adjusting method

Abstract

The invention belongs to the technical field of jacks, and discloses a chassis height adjustable jack which comprises a base protective cover, an adjustable base is movably connected to the interior of the base protective cover, a jacking assembly is movably connected to the top of the adjustable base, and the top of the jacking assembly abuts against the bottom of an automobile; the adjustable base comprises a base adjusting block which is clamped in the base protection cover in a sliding mode, a left positioning block and a right positioning block are movably clamped in the base adjusting block, a left linkage assembly and a right linkage assembly are further clamped in the base adjusting block in a sliding mode, and the upper end and the lower end of each linkage assembly are both connected with a shear type adjusting frame. Due to the arrangement of the adjustable base, the overall jacking height of the equipment can be effectively increased, and the equipment can quickly abut against the bottom of an automobile, so that the efficiency of jacking the automobile is greatly improved, and the potential safety hazard of temporarily replacing a spare tire during driving is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of jacks, and specifically relates to a jack with adjustable chassis height and an adjustment method. Background Art

[0002] A jack refers to a light lifting device that uses a rigid lifting member as a working device to lift a heavy object within a small stroke through a top bracket or a bottom pawl; jacks are mainly used in factories, mines, transportation and other departments for vehicle repair and other lifting and supporting work; its structure is light, strong, flexible and reliable, and can be carried and operated by one person. Common jacks mainly include two forms: manual and hydraulic.

[0003] In order to control costs, more and more automobile manufacturers will equip their cars with simple and practical manual scissor jacks. However, the lifting range of this type of jack is limited, which greatly restricts its applicability. Moreover, the chassis support surface is small and the support stability is poor. Once the car moves accidentally forward or backward during lifting, it is very likely to cause an accident and cause irreversible damage to the car chassis, resulting in great losses and potential safety hazards. Therefore, it is necessary to develop a new type of jack with adjustable chassis to solve the deficiencies in the existing technology. Summary of the Invention

[0004] To solve the problems raised in the above background art, the present invention provides a jack with adjustable chassis height and an adjustment method, which has the advantages of high applicability and better stability.

[0005] Among them, the adjustable base can effectively increase the overall lifting height of the device and enable the device to quickly abut against the bottom of the car, thus greatly improving the efficiency of lifting the car and reducing the potential safety hazards during temporary tire replacement while driving.

[0006] To achieve the above object, the present invention provides the following technical solution: A jack with adjustable chassis height, including a base protective cover, an adjustable base is movably connected inside the base protective cover, a lifting assembly is movably connected to the top of the adjustable base, and the top of the lifting assembly abuts against the bottom of the car;

[0007] The adjustable base includes a base adjustment block slidably clamped inside the base protective cover, two left and right positioning blocks are movably clamped inside the base adjustment block, two left and right linkage components are also slidably clamped inside the base adjustment block, a scissor adjustment frame is connected between the upper and lower ends of each linkage component and the bottom of the inner cavity of the base protective cover and the top of the inner cavity of the base adjustment block respectively, the scissor adjustment frame is hinged at both ends of the inner cavities of the base protective cover and the base adjustment block, an adjustment component is movably sleeved inside the two linkage components, and both ends of the adjustment component are respectively rotatably connected to the inside of the two positioning blocks.

[0008] Preferably, the side view of the base protective cover is a "U" - shaped structure, the side view of the base adjustment block is an inverted "U" - shaped, the base adjustment block is slidably clamped inside the base protective cover, and the height dimension of the base adjustment block is less than the height dimension of the inner cavity of the base protective cover.

[0009] Preferably, the scissor adjustment frame includes a linkage slider movably installed inside the base adjustment block. A linkage frame is integrally formed at both the front and rear ends of the linkage slider. Two linkage blocks are integrally formed at the end of the linkage frame away from the linkage slider, and the scissor adjustment frame is movably connected to the linkage assembly through the linkage blocks.

[0010] Preferably, a linkage sliding sleeve is provided in the middle of the linkage slider, and the linkage slider is slidably sleeved outside the adjustment component through the linkage sliding sleeve.

[0011] Preferably, the adjustment component includes an adjustment rod passing through the inside of the linkage sliding sleeve. A positioning shaft is integrally formed at both ends of the adjustment rod. The two positioning shafts are respectively rotatably sleeved inside the left and right positioning blocks through bearings. On the upper and lower sides of the outer surface of the adjustment rod, a number of symmetrically and evenly distributed positioning arc blocks are integrally formed. On the upper and lower sides of the outside of the adjustment rod, a number of symmetrically and evenly distributed limiting arc blocks are also provided. The outer surface of the limiting arc block is fixedly connected to the inside of the linkage sliding sleeve.

[0012] Preferably, the far - ends of the two positioning shafts respectively penetrate to the opposite sides of the two positioning blocks and extend outside the base adjustment block, and a linkage plate is fixedly connected to each of them. The opposite surfaces of the two linkage plates respectively fit against the outside of the base adjustment block and the positioning block, and a first adjustment ring is fixedly connected to the opposite surfaces of the two linkage plates.

[0013] Preferably, a number of limiting arc blocks and positioning arc blocks are alternately distributed. The distance between two adjacent positioning arc blocks is adapted to the width dimension of the limiting arc block, and the distance between two adjacent limiting arc blocks is adapted to the width dimension of the positioning arc block.

[0014] The arc length dimension between two vertically symmetric positioning arc blocks is greater than the arc length dimension of the limiting arc block. The outer surface of the adjustment rod is smooth, and the outer surfaces of the positioning arc block and the limiting arc block are rough.

[0015] Preferably, the jacking component includes two first support frames and two second support frames which are arranged directly above the base adjustment block and are mutually articulated. A holding seat is connected to the top of the connection end of the two second support frames, and a connection seat is connected to the bottom of the connection end of the two first support frames. The bottom of the connection seat is rotatably connected to the top of the base adjustment block.

[0016] A linkage frame is movably clamped inside the inner sides of the connection ends of the two first support frames and the second support frames. The front and rear ends of the linkage frame are rotationally connected to the two ends of the first support frame and the second support frame through short shafts. An adjusting lead screw is threadedly sleeved inside the two linkage frames. The two ends of the adjusting lead screw penetrate through the two linkage frames and are fixedly connected with a second adjusting ring.

[0017] Preferably, the connection seat includes an adjusting slider rotatably connected to the top of the base adjusting block. The adjusting slider and the inside of the abutting seat are fixedly connected with two connecting shafts on the left and right. The two first support frames and the second support frames are respectively connected to the inside of the adjusting slider and the abutting seat through the corresponding connecting shafts.

[0018] It includes the following operating steps:

[0019] S1. Quickly adjust the height difference between the top of the abutting seat and the bottom of the base protective cover according to the distance between the vehicle bottom and the ground;

[0020] S2. First, rotate the first adjusting ring and the linkage plate at either the left or right end. Then, the positioning shaft can drive the adjusting rod to rotate, and further make the positioning arc blocks on the upper and lower sides of its surface rotate 90 degrees along with it;

[0021] S3. At this time, the positioning arc blocks on the surface of the adjusting rod are misaligned with the limiting arc blocks fixedly connected to the inner wall of the linkage sliding sleeve, and ensure that the limiting arc blocks relatively move to between the two positioning arc blocks that are symmetrically arranged up and down;

[0022] S4. At this time, the limiting arc blocks can slide along the arc surface between the two positioning arc blocks that are symmetrically arranged up and down. Then, directly lift the jacking assembly. The scissor adjusting frame can be raised under the cooperation of the linkage assembly until the bottom of the base protective cover placed on the ground is adapted to the height of the top of the abutting seat and the vehicle bottom;

[0023] S5. Then, rotate the first adjusting ring and the linkage plate at either the left or right end again. The adjusting rod can drive the positioning arc blocks on its surface to rotate 90 degrees again, and make the limiting arc blocks on the inner wall of the linkage sliding sleeve relatively rotate to between two adjacent positioning arc blocks, so that the limiting arc blocks and the positioning arc blocks are closely and alternately distributed again;

[0024] S6. Then, with the cooperation of the adjusting slider, place the base protective cover and the entire adjustable base in the long axis direction parallel to the lower side of the vehicle bottom side beam, while the long axis direction of the entire jacking assembly is perpendicular to the lower side of the vehicle bottom side beam;

[0025] S7. Then, rotate a second adjusting ring located in the front, which can drive the adjusting lead screw to rotate, and further drive the front and rear two linkage frames to approach each other, so that the first support frame and the second support frame that are connected through the abutting seat and the adjusting slider are raised, thereby jacking up the vehicle with the cooperation of the abutting seat.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] 1. Due to the setting of the adjustable base in the present invention, it can not only effectively increase the overall jacking height of the device, but also enable the device to quickly abut against the bottom of the vehicle, thereby greatly improving the efficiency of jacking the vehicle and reducing the safety hazards of temporarily replacing the spare tire during driving.

[0028] 2. Due to the setting of the adjustable base in the present invention, the abutting seat can quickly abut against the side beam of the vehicle, which helps to improve the calibration effect between the abutting seat and the side beam, and avoid the instability factors when the abutting seat abuts against the bottom of the side beam through the jacking component, thereby improving the safety and stability of the support.

[0029] 3. Due to the setting of the adjustable base in the present invention, it not only improves the jacking range and increases its applicable range, but also realizes the quick jacking and equipment storage efficiency through the adjustable base, reduces the usage fatigue, improves the usage comfort, and increases the market competitiveness of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a schematic structural diagram of the present invention;

[0031] Figure 2 is a front view of the present invention;

[0032] Figure 3 is a side view of the present invention;

[0033] Figure 4 is a schematic structural diagram of the adjustable base of the present invention;

[0034] Figure 5 is a cross-sectional view of the front of the adjustable base of the present invention;

[0035] Figure 6 is a schematic structural diagram of the adjusting component of the present invention;

[0036] Figure 7 is a schematic structural diagram of the linkage component of the present invention.

[0037] In the figure: 1. Base protective cover; 2. Adjustable base; 21. Base adjustment block; 22. Positioning block; 23. Linkage assembly; 231. Linkage slider; 232. Linkage frame; 233. Linkage block; 234. Linkage sliding sleeve; 24. Scissor adjustment frame; 25. Adjustment assembly; 251. Adjustment rod; 252. Positioning arc block; 253. Positioning shaft; 254. Limiting arc block; 26. Linkage plate; 27. First adjustment ring; 3. Jacking assembly; 31. First support frame; 32. Second support frame; 33. Supporting seat; 34. Connecting seat; 341. Adjustment slider; 342. Connecting shaft; 35. Linkage frame; 36. Adjusting screw rod; 37. Second adjustment ring. Detailed implementation manner

[0038] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0039] As Figures 1 to 7 shown, the present invention provides a jack with adjustable chassis height, including a base protective cover 1. An adjustable base 2 is movably connected inside the base protective cover 1. A jacking assembly 3 is movably connected to the top of the adjustable base 2. The top of the jacking assembly 3 abuts against the bottom of the vehicle. Due to the setting of the adjustable base 2, not only the jacking range is increased, and its applicable range is expanded, but also the quick jacking and equipment storage efficiency are realized through the adjustable base 2, the use fatigue is reduced, the use comfort is improved, and the market competitiveness of the equipment is increased.

[0040] The adjustable base 2 includes a base adjustment block 21 that is slidably clamped inside the base protective cover 1. Two left and right positioning blocks 22 are movably clamped inside the base adjustment block 21. Two left and right linkage assemblies 23 are also slidably clamped inside the base adjustment block 21. A scissor adjustment frame 24 is connected between the upper and lower ends of the linkage assembly 23 and the bottom of the inner cavity of the base protective cover 1 and the top of the inner cavity of the base adjustment block 21. The scissor adjustment frame 24 is hinged at both ends of the inner cavities of the base protective cover 1 and the base adjustment block 21. An adjustment assembly 25 is movably sleeved inside the two linkage assemblies 23. Both ends of the adjustment assembly 25 are respectively rotatably connected to the inside of the two positioning blocks 22. Due to the setting of the adjustable base 2, not only can the overall jacking height of the equipment be effectively increased, but also the equipment can quickly abut against the bottom of the vehicle, thereby greatly improving the efficiency of jacking the vehicle and reducing the safety hazard of temporarily replacing the spare tire during driving.

[0041] Among them, the side view of the base protective cover 1 is a "U" - shaped structure, and the side view of the base adjusting block 21 is an inverted "U" - shaped. The base adjusting block 21 is slidably clamped inside the base protective cover 1, and the height dimension of the base adjusting block 21 is smaller than the height dimension of the inner cavity of the base protective cover 1. Due to the setting of the base adjusting block 21, it is convenient to integrate the linkage assembly 23, the scissor adjusting frame 24, etc., and effectively reduces the overall integration height of the equipment, making it applicable to vehicles with a lower chassis.

[0042] Among them, the scissor adjusting frame 24 includes a linkage slider 231 movably installed inside the base adjusting block 21. A linkage frame 232 is integrally formed at both the front and rear ends of the linkage slider 231. Two linkage blocks 233, one above and one below, are integrally formed at the end of the linkage frame 232 far from the linkage slider 231. The scissor adjusting frame 24 is movably connected to the linkage assembly 23 through the linkage blocks 233. Due to the setting of the linkage frame 232, it is convenient for several linkage blocks 233 to be synchronously linked with the linkage slider 231, and it can reduce the material usage while ensuring the support strength, reducing the cost and the overall weight.

[0043] Among them, a linkage sliding sleeve 234 is provided in the middle of the linkage slider 231, and the linkage slider 231 is slidably sleeved outside the adjusting assembly 25 through the linkage sliding sleeve 234.

[0044] Among them, the adjusting assembly 25 includes an adjusting rod 251 passing through the inside of the linkage sliding sleeve 234. A positioning shaft 253 is integrally formed at both ends of the adjusting rod 251. The two positioning shafts 253 are respectively rotatably sleeved inside the left and right positioning blocks 22 through bearings. On the upper and lower sides of the outer surface of the adjusting rod 251, a number of symmetrically and evenly distributed positioning arc blocks 252 are integrally formed. On the upper and lower sides outside the adjusting rod 251, a number of symmetrically and evenly distributed limiting arc blocks 254 are also provided. The outer surface of the limiting arc block 254 is fixedly connected to the inside of the linkage sliding sleeve 234. Due to the setting of the positioning shaft 253, it can ensure that the adjusting rod 251 can rotate smoothly inside the base protective cover 1 and the base adjusting block 21 under the restriction of the positioning blocks 22, thereby driving the two linkage assemblies 23 to move away from or close to each other smoothly.

[0045] Among them, the far - ends of the two positioning shafts 253 respectively penetrate to the opposite sides of the two positioning blocks 22 and extend outside the base adjusting block 21, and a linkage plate 26 is fixedly connected to each. The opposite surfaces of the two linkage plates 26 are respectively attached to the outside of the base adjusting block 21 and the positioning block 22, and a first adjusting ring 27 is fixedly connected to the opposite surface of each of the two linkage plates 26.

[0046] Among them, several limiting arc blocks 254 and positioning arc blocks 252 are alternately distributed. The distance between two adjacent positioning arc blocks 252 is adapted to the width dimension of the limiting arc block 254, and the distance between two adjacent limiting arc blocks 254 is adapted to the width dimension of the positioning arc block 252. Due to the arrangement of the limiting arc blocks 254 and the positioning arc blocks 252, the misaligned positioning arc blocks 252 and limiting arc blocks 254 can ensure that the linkage assembly 23 can slide quickly along the outside of the adjusting assembly 25, so as to achieve the effect of quickly adjusting the support height of the scissor adjusting frame 24. At the same time, it is also convenient to ensure that the linkage assembly 23 is stably sleeved on the outside of the adjusting assembly 25 through the closely alternating positioning arc blocks 252 and limiting arc blocks 254 of the scissor adjusting frame 24, so as to ensure that the support height of the scissor adjusting frame 24 remains stable.

[0047] The arc length dimension between two symmetrically positioned positioning arc blocks 252 above and below is greater than the arc length dimension of the limiting arc block 254. The outer surface of the adjusting rod 251 is smooth, and the outer surfaces of the positioning arc block 252 and the limiting arc block 254 are rough.

[0048] Among them, the jacking assembly 3 includes two first support frames 31 and two second support frames 32 that are arranged directly above the base adjusting block 21 and are mutually connected. The top of the connecting end of the two second support frames 32 is connected with a holding seat 33, and the bottom of the connecting end of the two first support frames 31 is connected with a connecting seat 34. The bottom of the connecting seat 34 is rotatably connected to the top of the base adjusting block 21. Due to the setting of the adjustable base 2, the holding seat 33 can quickly hold against the side beam of the vehicle, which helps to improve the calibration effect between the holding seat 33 and the side beam, and avoid the instability factors when the holding seat 33 holds against the bottom of the side beam through the jacking assembly 3, thereby improving the safety and stability of the support.

[0049] A linkage frame 35 is movably clamped inside the connecting ends of the two first support frames 31 and the second support frames 32. The front and rear ends of the linkage frame 35 are rotatably connected to the two ends of the first support frame 31 and the second support frame 32 through short shafts. An adjusting screw rod 36 is threadedly sleeved inside the two linkage frames 35. The two ends of the adjusting screw rod 36 penetrate through the two linkage frames 35 and are fixedly connected with a second adjusting ring 37.

[0050] Among them, the connecting seat 34 includes an adjusting slider 341 rotatably connected to the top of the base adjusting block 21. Inside both the adjusting slider 341 and the abutting seat 33, two left and right connecting shafts 342 are fixedly connected. Both the two first support frames 31 and the second support frame 32 are respectively connected to the inside of the adjusting slider 341 and the abutting seat 33 through the corresponding connecting shafts 342. Due to the setting of the adjusting slider 341, the entire lifting assembly 3 can rotate relative to the base protective cover 1 and the adjustable base 2 as a whole, thereby ensuring that the second adjusting rings 37 at both ends of the lifting assembly 3 are convenient for operation by the operator. At the same time, it ensures that the length of the base protective cover 1 and the adjustable base 2 as a whole is parallel to the vehicle bottom, avoiding the situation where the vehicle bottom is damaged due to the vehicle slipping during the lifting process and causing the equipment to tip over.

[0051] The following operation steps are included:

[0052] S1. Quickly adjust the height difference between the top of the abutting seat 33 and the bottom of the base protective cover 1 according to the distance between the vehicle bottom and the ground;

[0053] S2. First, rotate the first adjusting ring 27 and the linkage plate 26 at either the left or right end. Then, the positioning shaft 253 can drive the adjusting rod 251 to rotate, and further make the positioning arc blocks 252 on the upper and lower sides of its surface rotate 90 degrees following its rotation;

[0054] S3. At this time, the positioning arc block 252 on the surface of the adjusting rod 251 is misaligned with the limiting arc block 254 fixedly connected to the inner wall of the linkage sliding sleeve 234, and ensure that the limiting arc block 254 relatively moves between the two positioning arc blocks 252 that are symmetrically arranged up and down;

[0055] S4. At this time, the limiting arc block 254 can slide along the arc surface between the two positioning arc blocks 252 that are symmetrically arranged up and down. Then, directly lift the lifting assembly 3, and the scissor adjusting frame 24 can be raised under the cooperation of the linkage assembly 23 until the bottom of the base protective cover 1 placed on the ground and the top of the abutting seat 33 are adapted to the height of the vehicle bottom;

[0056] S5. Then, rotate the first adjusting ring 27 and the linkage plate 26 at either the left or right end again. The adjusting rod 251 can drive the positioning arc block 252 on its surface to rotate 90 degrees again, and make the limiting arc block 254 on the inner wall of the linkage sliding sleeve 234 relatively rotate between two adjacent positioning arc blocks 252, so that the limiting arc block 254 and the positioning arc block 252 are closely and alternately distributed again;

[0057] S6. Then, with the cooperation of the adjusting slider 341, place the long axis direction of the base protective cover 1 and the adjustable base 2 as a whole directly below the vehicle bottom side beam, while the long axis direction of the entire lifting assembly 3 is perpendicular to directly below the vehicle bottom side beam;

[0058] S7. Then rotate a second adjusting ring 37 located in the front, which can drive the adjusting screw rod 36 to rotate, and further drive the two linkage frames 35 in the front and back to approach each other, so that the first support frame 31 and the second support frame 32 that are connected to each other through the abutting seat 33 and the adjusting slider 341 are raised, thereby jacking up the vehicle with the cooperation of the abutting seat 33.

[0059] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device.

[0060] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An adjustable chassis height jack, including a base protective cover (1), characterized in that: An adjustable base (2) is movably connected inside the base protective cover (1), and a jacking assembly (3) is movably connected to the top of the adjustable base (2), and the top of the jacking assembly (3) abuts against the bottom of the vehicle. The adjustable base (2) includes a base adjustment block (21) slidably clamped inside the base protective cover (1). Inside the base adjustment block (21), there are two positioning blocks (22) movably clamped on the left and right. Inside the base adjustment block (21), there are also two linkage assemblies (23) slidably clamped on the left and right. A scissor adjustment frame (24) is connected between the upper and lower ends of each linkage assembly (23) and the bottom of the inner cavity of the base protective cover (1) and the top of the inner cavity of the base adjustment block (21). The scissor adjustment frame (24) is hinged at both ends of the inner cavities of the base protective cover (1) and the base adjustment block (21). An adjustment assembly (25) is movably sleeved inside the two linkage assemblies (23), and the two ends of the adjustment assembly (25) are respectively rotatably connected to the inside of the two positioning blocks (22).

2. The adjustable chassis height jack according to claim 1, characterized in that: The side view of the base protective cover (1) is a "U" - shaped structure, and the side view of the base adjustment block (21) is an inverted "U" - shaped. The base adjustment block (21) is slidably clamped inside the base protective cover (1), and the height dimension of the base adjustment block (21) is smaller than the height dimension of the inner cavity of the base protective cover (1).

3. The adjustable chassis height jack according to claim 1, characterized in that: The scissor adjustment frame (24) includes a linkage slider (231) movably installed inside the base adjustment block (21). A linkage frame (232) is integrally formed at both the front and rear ends of the linkage slider (231). Two linkage blocks (233) are integrally formed at the upper and lower ends of the linkage frame (232) away from the linkage slider (231). The scissor adjustment frame (24) is movably connected to the linkage assembly (23) through the linkage blocks (233).

4. The adjustable chassis height jack according to claim 3, characterized in that: A linkage sliding sleeve (234) is formed in the middle of the linkage slider (231), and the linkage slider (231) is slidably sleeved outside the adjustment assembly (25) through the linkage sliding sleeve (234).

5. The chassis height adjustable jack according to claim 4, characterized in that: The adjustment assembly (25) includes an adjustment rod (251) passing through the inside of the linkage sliding sleeve (234). A positioning shaft (253) is integrally formed at both ends of the adjustment rod (251). The two positioning shafts (253) are respectively rotatably sleeved inside the two positioning blocks (22) through bearings. A number of positioning arc blocks (252) are integrally formed on the upper and lower sides of the outer surface of the adjustment rod (251) symmetrically and evenly distributed. A number of limiting arc blocks (254) are also symmetrically and evenly distributed on the upper and lower sides of the outside of the adjustment rod (251). The outer surface of the limiting arc block (254) is fixedly connected to the inside of the linkage sliding sleeve (234).

6. The adjustable chassis height jack according to claim 5, characterized in that: The distal ends of the two positioning shafts (253) respectively penetrate through the opposite back surfaces of the two positioning blocks (22) and extend to the outside of the base adjusting block (21), and a linkage plate (26) is fixedly connected to each of them. The opposite surfaces of the two linkage plates (26) are respectively attached to the outside of the base adjusting block (21) and the positioning block (22), and a first adjusting ring (27) is fixedly connected to the opposite back surfaces of the two linkage plates (26).

7. The adjustable chassis height jack according to claim 5, characterized in that: A number of limiting arc blocks (254) and positioning arc blocks (252) are alternately distributed. The distance between two adjacent positioning arc blocks (252) is adapted to the width dimension of the limiting arc block (254), and the distance between two adjacent limiting arc blocks (254) is adapted to the width dimension of the positioning arc block (252); The arc length dimension between two vertically symmetric positioning arc blocks (252) is greater than the arc length dimension of the limiting arc block (254). The outer surface of the adjusting rod (251) is smooth, and the outer surfaces of the positioning arc block (252) and the limiting arc block (254) are rough.

8. The adjustable chassis height jack according to claim 1, wherein: The jacking assembly (3) includes two first support frames (31) and two second support frames (32) which are arranged directly above the base adjusting block (21) and are mutually articulated. The top of the connecting end of the two second support frames (32) is connected with a holding seat (33), and the bottom of the connecting end of the two first support frames (31) is connected with a connecting seat (34). The bottom of the connecting seat (34) is rotatably connected to the top of the base adjusting block (21); A linkage frame (35) is movably clamped inside the connecting ends of the two first support frames (31) and the second support frames (32). The front and rear ends of the linkage frame (35) are rotatably connected to the two ends of the first support frame (31) and the second support frame (32) through short shafts. An adjusting screw rod (36) is threadedly sleeved inside the two linkage frames (35). The two ends of the adjusting screw rod (36) penetrate through the two linkage frames (35) and are fixedly connected with a second adjusting ring (37).

9. The adjustable chassis height jack according to claim 8, characterized in that: The connecting seat (34) includes an adjusting slider (341) rotatably connected to the top of the base adjusting block (21). Inside the adjusting slider (341) and the holding seat (33), two left and right connecting shafts (342) are fixedly connected. The two first support frames (31) and the second support frames (32) are respectively connected to the inside of the adjusting slider (341) and the holding seat (33) through the corresponding connecting shafts (342).

10. A chassis height adjustable jack and an adjustment method according to claims 1-9, characterized in that, It includes the following operating steps: S1. Quickly adjust the height difference between the top of the holding seat (33) and the bottom of the base protective cover (1) according to the distance between the vehicle bottom and the ground; S2. First, rotate the first adjusting ring (27) and the linkage plate (26) at either the left or right end. Then, the adjusting rod (251) can be driven to rotate through the positioning shaft (253), and thus the positioning arc blocks (252) on the upper and lower sides of its surface will follow it and rotate 90 degrees; S3. At this time, the positioning arc block (252) on the surface of the adjusting rod (251) can be misaligned with the limiting arc block (254) fixedly connected to the inner wall of the linkage sliding sleeve (234), and it is ensured that the limiting arc block (254) relatively moves between the two positioning arc blocks (252) that are symmetrically distributed up and down; S4. At this time, the limiting arc block (254) can slide along the arc surface between the two positioning arc blocks (252) that are symmetrically distributed up and down, and then directly lift the jacking assembly (3) upward. Then, with the cooperation of the linkage assembly (23), the scissor adjusting frame (24) can be raised until the bottom of the base protection cover (1) placed on the ground is adapted to the height of the top of the abutment seat (33) and the vehicle bottom; S5. Then rotate either the left or right first adjusting ring (27) and the linkage plate (26), and the adjusting rod (251) can drive the positioning arc block (252) on its surface to rotate 90 degrees again, and the limiting arc block (254) on the inner wall of the linkage sliding sleeve (234) relatively rotates between two adjacent positioning arc blocks (252), so that the limiting arc block (254) and the positioning arc block (252) are closely and alternately distributed again; S6. Then, with the cooperation of the adjusting slider (341), the long axis direction of the whole base protection cover (1) and the adjustable base (2) is placed parallel to the lower side of the vehicle bottom side beam, while the long axis direction of the whole jacking assembly (3) is perpendicular to the lower side of the vehicle bottom side beam; S7. Then rotate a second adjusting ring (37) located in the front, which can drive the adjusting screw rod (36) to rotate, and then drive the front and rear two linkage frames (35) to approach each other, so that the first support frame (31) and the second support frame (32) that are connected through the abutment seat (33) and the adjusting slider (341) are raised, thereby jacking up the vehicle with the cooperation of the abutment seat (33).

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